NCERT Solutions For Class 11 Geography Chapter 8 Solar Radiation Heat Balance and Temperature - 2025-26

1. Multiple Choice Questions.

i. The sun is directly overhead at noon on 21st June at:

• (a) The equator
• (b) 23.5° S
• (c) 23.5° N
• (d) 66.5° N

Answer: (c) 23.5° N

ii. In which one of the following cities, are the days the longest?

• (a) Tiruvanantpuram
• (b) Chandigarh
• (c) Hyderabad
• (d) Nagpur

Answer: (b) Chandigarh

iii. The atmosphere is mainly heated by the:

• (a) Short wave solar radiation
• (b) Reflected solar radiation
• (c) Long wave terrestrial radiation
• (d) Scattered solar radiation

Answer: (c) Long wave terrestrial radiation

iv. Make correct pairs from the following two columns.

v. The main reason that the earth experiences highest temperatures in the subtropics in the northern hemisphere rather than at the equator is:

• (a) Subtropical areas tend to have less cloud cover than equatorial areas.
• (b) Subtropical areas have longer day hours in the summer than the equatorial.
• (c) Subtropical areas have an enhanced “green house effect” compared to equatorial areas.
• (d) Subtropical areas are nearer to the oceanic areas than the equatorial locations.

Answer: (a) Subtropical areas tend to have less cloud cover than equatorial areas.

2. Answer the following questions in about 30 words.

i. How does the unequal distribution of heat over the planet earth in space and time cause variations in weather and climate?

Answer: Unequal distribution of heat on earth leads to differences in temperature and atmospheric pressure which, in turn, create wind and ocean currents. These circulation patterns cause variations in weather and, over longer periods, create different climatic zones across the globe.

ii. What are the factors that control temperature distribution on the surface of the earth?

Answer: The main factors controlling temperature distribution are latitude, altitude, distance from the sea, air-mass circulation, presence of warm and cold ocean currents, and local aspects such as the slope and orientation of land.

iii. In India, why is the day temperature maximum in May and why not after the summer solstice?

Answer: In India, maximum day temperatures are observed in May because by June, cloud cover and onset of monsoon rains lower the day temperatures. After summer solstice, increased moisture and rainfall bring cooling effects.

iv. Why is the annual range of temperature high in the Siberian plains?

Answer: The annual range of temperature is high in the Siberian plains due to their continental location, far from moderating influence of oceans, leading to extremely cold winters and hot summers.

3. Answer the following questions in about 150 words.

i. How do the latitude and the tilt in the axis of rotation of the earth affect the amount of radiation received at the earth’s surface?

Answer: The latitude of a place affects the angle at which the sun’s rays strike the earth's surface. Near the equator, rays are more direct and concentrated, giving higher temperatures, while at higher latitudes, rays are slant and spread over a larger area, resulting in less heating.

The tilt of the Earth's axis (23.5°) causes seasonal variation in solar radiation received at different latitudes during earth's revolution around the sun. This variation leads to changes in day length, angle of incidence of the sun's rays, and intensity of insolation, giving rise to seasons. Thus, both latitude and tilt decide the energy received from the sun and the pattern of temperature distribution across the globe.

ii. Discuss the processes through which the earth-atmosphere system maintains heat balance.

Answer: The earth-atmosphere system maintains heat balance through several processes. The earth receives solar radiation (insolation) mainly as short waves. Some of this is reflected back by clouds, atmosphere, and earth’s surface (albedo). The rest is absorbed by the earth's surface and the atmosphere. The absorbed energy is returned to space as long wave terrestrial radiation. The atmosphere absorbs part of this outgoing radiation, especially due to greenhouse gases, and also radiates heat back to space.

Latitudinal redistribution of heat occurs through winds and ocean currents. Through this continuous input and output, the total heat of earth’s system remains balanced, preventing excessive heating or cooling.

iii. Compare the global distribution of temperature in January over the northern and southern hemisphere of the earth.

Answer: In January, the northern hemisphere experiences winter and has lower temperatures, with isotherms bending southwards over land and northwards over oceans. Eurasian interior sees extreme cold, while western Europe is warmer due to oceanic influence.

In the southern hemisphere, it is summer and temperatures are higher, but due to the dominance of oceans, there is less temperature variation. Isotherms in the southern hemisphere run nearly parallel to the latitudes, showing a more gradual temperature change, while in the north, continentality results in greater extremes.

Solar Radiation, Heat Balance and Temperature – NCERT Solutions 2025-26

Mastering Solar Radiation, Heat Balance and Temperature is vital for Geography exams. With NCERT solutions, students build a clear foundation on how the sun’s energy shapes Earth's climate and weather. Focus on core definitions and diagrams for strong conceptual understanding.

Pay close attention to factors like insolation, terrestrial radiation, and temperature inversion. These core topics are frequently asked in exams and are crucial for high-scoring answers. Remember to practice the NCERT exercises regularly for comprehensive preparation.

Regular revision of NCERT chapter-wise solutions helps you boost your exam confidence. Understand distribution patterns, use labelled diagrams, and relate concepts to real-world examples to enhance your answers and perform your best in the Geography board exams.

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